From patchwork Fri Aug 7 09:12:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Yang X-Patchwork-Id: 11705211 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 17043722 for ; Fri, 7 Aug 2020 09:14:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DC04F22C9F for ; Fri, 7 Aug 2020 09:14:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC04F22C9F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 230978D009D; Fri, 7 Aug 2020 05:14:21 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 1E2908D0097; Fri, 7 Aug 2020 05:14:21 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 120058D009D; Fri, 7 Aug 2020 05:14:21 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0104.hostedemail.com [216.40.44.104]) by kanga.kvack.org (Postfix) with ESMTP id EE9AF8D0097 for ; Fri, 7 Aug 2020 05:14:20 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id AD77AE09F for ; Fri, 7 Aug 2020 09:14:20 +0000 (UTC) X-FDA: 77123211480.19.coach74_4e09d8526fbf Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id 7EFB71AD1B2 for ; Fri, 7 Aug 2020 09:14:20 +0000 (UTC) X-Spam-Summary: 1,0,0,79fd8a150e300a9c,d41d8cd98f00b204,richard.weiyang@linux.alibaba.com,,RULES_HIT:41:355:379:541:960:973:988:989:1260:1261:1311:1314:1345:1359:1437:1515:1534:1540:1711:1714:1730:1747:1777:1792:2393:2553:2559:2562:2902:3138:3139:3140:3141:3142:3350:3865:3867:3871:3872:4250:4321:5007:6119:6261:7903:9010:9012:10004:11026:11473:11658:11914:12043:12296:12297:12438:12555:12895:12986:13069:13172:13229:13311:13357:13894:14096:14181:14384:14394:14721:21080:21627:21939:21990:30054:30065:30090,0,RBL:115.124.30.45:@linux.alibaba.com:.lbl8.mailshell.net-64.201.201.201 62.20.2.100;04y8116ih6ykf8jach4jbfheeykbsycm7at8h5ybb5nzooohanwr1533ndm7ps4.ua4y4j13qnyunjoz5ynr1cdb1xsfj9mgk5w6yeeo49z5hg41a1kpbjq5i7o8fnb.n-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:23,LUA_SUMMARY:none X-HE-Tag: coach74_4e09d8526fbf X-Filterd-Recvd-Size: 2125 Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by imf16.hostedemail.com (Postfix) with ESMTP for ; Fri, 7 Aug 2020 09:14:19 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R971e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01358;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0U5.Byex_1596791596; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U5.Byex_1596791596) by smtp.aliyun-inc.com(127.0.0.1); Fri, 07 Aug 2020 17:13:16 +0800 From: Wei Yang To: mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wei Yang Subject: [PATCH 02/10] mm/hugetlb: make sure to get NULL when list is empty Date: Fri, 7 Aug 2020 17:12:43 +0800 Message-Id: <20200807091251.12129-3-richard.weiyang@linux.alibaba.com> X-Mailer: git-send-email 2.20.1 (Apple Git-117) In-Reply-To: <20200807091251.12129-1-richard.weiyang@linux.alibaba.com> References: <20200807091251.12129-1-richard.weiyang@linux.alibaba.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 7EFB71AD1B2 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000017, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: list_first_entry() may not return NULL even when the list is empty. Let's make sure the behavior by using list_first_entry_or_null(), otherwise it would corrupt the list. Signed-off-by: Wei Yang --- mm/hugetlb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 62ec74f6d03f..0a2f3851b828 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -237,7 +237,8 @@ get_file_region_entry_from_cache(struct resv_map *resv, long from, long to) VM_BUG_ON(resv->region_cache_count <= 0); resv->region_cache_count--; - nrg = list_first_entry(&resv->region_cache, struct file_region, link); + nrg = list_first_entry_or_null(&resv->region_cache, + struct file_region, link); VM_BUG_ON(!nrg); list_del(&nrg->link);